JP2008185661A - Endless belt, fixing device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt which achieves improvement of durability at one side end or both side ends of the endless belt, and prevents the occurrence of buckling of the endless belt or wear deformation at the end of the endless belt and cracking leading to the breakage of the belt without requiring a complicated system. <P>SOLUTION: The endless belt is equipped with a lubricant holding part at one side end or at each of both side ends of a belt main body. It is desirable that the holding part is a porous body or a recessed groove opening toward the outside in parallel with the shaft direction of the belt in the circumferential direction of the end face of the belt, and it is more desirable that a part of the surface of the porous body is covered with a reinforcing member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an endless belt, a fixing member, and an image forming apparatus.

  In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, for example, a photosensitive member (photosensitive drum) formed in a drum shape is uniformly charged, and the photosensitive drum is controlled based on image information. The light is exposed to light to form an electrostatic latent image on the photosensitive drum. Then, the electrostatic latent image is converted into a visible image (toner image) with toner, the toner image is primarily transferred from the photosensitive drum to the intermediate transfer belt, and then further transferred from the intermediate transfer belt to the recording paper. The toner image is fixed on the recording paper by a fixing device.

As a conventional fixing device, for example, a rotatable heating fixing roll having a heating source, an endless belt that is pressed against the heating fixing roll and driven with the heating roll, and disposed inside the endless belt, A pressing member that presses the endless belt against the heating roll and forms a pressure contact area (nip portion) between the endless belt and the heat fixing roll, and is disposed in a state of being fitted inside both end portions of the endless belt. A belt guide member that rotatably guides the inner surface of the endless belt, and passing the sheet through the contact area to fix the unfixed toner image on the sheet by heat and pressure. In this type of fixing device (belt nip type), the endless belt is controlled by the meandering prevention members at both ends. However, if the number of times the endless belt hits the meandering prevention member disposed on both end faces increases due to the long-term use of the fixing device, the endless belt is worn by sliding with the meandering prevention member, and the endless belt There was a possibility that cracks occurred at the ends of the slabs, and in the worst case, the ruptures could occur.
The occurrence of such cracks and breaks at the end of the belt is not limited to the fixing device of the belt nip method, but is a common problem in a fixing system using an endless belt. Improvement of the control system in the belt driving system In addition, improvement is achieved by increasing the durability of the belt itself.

For example, as an improvement of the belt drive system, a structure in which the pressure contact portion of the belt meandering prevention member with the edge surface of the belt member is configured to be elastically deformable (see, for example, Patent Document 1), and a belt. As an improvement by improving its own durability, a heat-resistant coating layer is provided on the outer surface and / or inner surface of the peripheral edge of the belt, or a heat-resistant tape is attached (for example, Patent Document 2), a belt metal layer having both end portions thicker than the central portion (see, for example, Patent Document 3), and a belt outer peripheral layer having a rubber layer, the rubber If the belt end is covered with a layer (see, for example, Patent Document 4), or a groove is formed along the belt circumference at the belt longitudinal end, the belt end surface will grow even if cracks occur. Restrain and belt That ensuring grace period until loss (e.g., Patent Document 5 reference.) Have been proposed.
JP 2006-0665250 A JP-A-5-345369 JP 2005-31474 A JP 2005-55469 A JP 2006-138944 A

However, the conventional technique has the following problems.
That is, the improvement in the belt drive system is not preferable because the cost increases as compared with a simple butting type guide. Therefore, it is preferable to improve by improving the durability of the belt itself, and it is most effective to increase the film thickness of the belt, but the paper is peeled off due to the increase in cost and the decrease in flexibility of the belt. Defects will occur. Further, if the thickness is increased while maintaining only the film thickness at the belt end, the manufacturing cost increases. In addition, a belt with a heat-resistant coating layer or heat-resistant tape or a reinforcing rib such as silicone rubber added to the end of the belt has insufficient wear resistance and repeated fatigue durability against rotational sliding with the meandering prevention member. The rotational sliding resistance with the meandering prevention members provided at both end portions of the endless belt cannot be stably maintained over a long period of time.

Therefore, the present invention does not require a complicated system, and the durability of one or both ends of the endless belt is improved, and cracks that lead to endless belt excavation or wear deformation or belt breakage of the endless belt end. It is an object of the present invention to provide an endless belt capable of preventing the occurrence of the above-mentioned.
Another object of the present invention is to provide a highly durable electrophotographic fixing device and an image forming apparatus using the endless belt.

In order to achieve the above object, the present inventors have conducted research on an endless belt, an electrophotographic fixing device, and an image forming apparatus. As a result, the present invention has been completed.
That is, the present invention

<1> An endless belt including a lubricant holding portion that holds a lubricant at one or both ends of the belt main body.

<2> The endless belt according to <1>, wherein the lubricant holding portion is provided on an inner peripheral surface of the belt main body.

<3> The endless belt according to <1> or <2>, wherein the lubricant holding portion is provided on an outer peripheral surface of the belt main body.

<4> The endless belt according to <1>, wherein the lubricant holding portion includes a porous body.

<5> The endless belt according to <4>, further comprising a reinforcing member for reinforcing the porous body.

<6> The endless as described in <1>, wherein the lubricant holding portion has a concave groove that opens outward in parallel with the belt axial direction along the circumferential direction of the end surface of the belt main body. It is a belt.

<7> An endless belt having a fixing member, a lubricant holding portion for holding a lubricant at one or both ends of the belt main body, and an inner side of the endless belt, the endless belt being pressed against the fixing member And a pressing member that forms a contact portion between the fixing member and the endless belt.

<8> The fixing device according to <7>, further comprising a meandering prevention member that contacts an end surface of the endless belt and prevents meandering of the endless belt.

<9> An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming a latent image on the surface of the image carrier, and developing the latent image with toner to form a toner image Developing means, transfer means for transferring the toner image to a recording medium, and fixing means for heat-fixing the toner image on the recording medium,
The fixing means is disposed on a fixing member, an endless belt that includes a lubricant holding portion that holds a lubricant at one or both ends of the belt body, and the endless belt is disposed inside the endless belt. An image forming apparatus, comprising: a fixing device having a pressing member that presses against the pressing member to form a contact portion between the fixing member and the endless belt.

According to the present invention, a complicated system is not required, endurance of one or both ends of the endless belt is improved, and cracks that lead to endless belt excavation or wear deformation or belt breakage of the endless belt end. It is possible to provide an endless belt that can prevent the occurrence of.
Further, according to the present invention, it is possible to provide a highly durable electrophotographic fixing device and an image forming apparatus using the endless belt.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the endless belt of the present invention will be described, and then the fixing device of the present invention and the image forming apparatus of the present invention using the belt will be described.

<Endless belt>
The endless belt of the present invention (hereinafter sometimes simply referred to as “belt”) is characterized in that a lubricant holding portion is provided at one or both ends of the belt main body.
The endless belt of the present invention only needs to have a lubricant holding portion at one end or both ends of the belt main body, and the material, shape, size, and the like are not particularly limited. The belt body may have a single layer structure or a multilayer structure.

Embodiments of the endless belt of the present invention will be described with reference to the drawings.
First, FIG. 7 is a cross-sectional view showing a belt body formed by forming a coating layer containing a thermoplastic resin on a base layer, that is, an endless belt having a conventional configuration. An example of the endless belt of the present invention has a configuration in which a lubricant holding portion is provided at the end of the belt body.
Specifically, FIG. 1 is a cross-sectional view showing an example of an endless belt of the present invention having a configuration in which a porous body 22 is provided as an lubricant holding portion 20a at an end portion of the belt body 10. As shown in FIG. 1, the porous body 22 is disposed and joined so as to contact the edge of the belt main body 10.
FIG. 2 is a cross-sectional view showing an example of the endless belt according to the present invention having a configuration in which a porous body 22 is provided as a lubricant holding portion 20b at the end of the belt body 10 and a reinforcing member 24 is further added. . As shown in FIG. 2, the porous body 22 is provided in the same manner as in FIG. 1, and the reinforcing member 24 covers a part of the porous body 22.
3 is a cross-sectional view showing an example of an endless belt according to the present invention having a configuration in which an end of the belt body 10 is provided with a groove 29 that opens outward in the belt axial direction as a lubricant holding portion 20c. FIG. As shown in FIG. 3, the concave groove 29 is formed by bonding a concave groove forming member 26 to the base layer 12 of the belt body 10 via a bonding agent 28.

  In a belt nip type fixing device, a lubricant is usually supplied between the pressing member and the belt inner surface in order to reduce sliding resistance between the pressing member and the belt inner surface inside the endless belt. Low viscosity silicone oil is often used to obtain resistance. For this reason, with the use of the fixing device, the lubricating oil goes around to the belt end side, but in the conventional endless belt, it does not stay at the belt end and falls from the belt end and stains the inside of the device, Alternatively, the recording medium is soiled around the belt surface (outer periphery), or the image is soiled.

  In contrast, in the endless belt of the present invention in which the lubricant holding portion is provided on one or both ends of the belt body, the lubricant remains in the lubricant holding portion, and the sliding resistance with the belt guide sliding surface Can be kept low over a long period of time. As a result, it is possible to effectively prevent the occurrence of cracks that lead to wear deformation and belt breakage at the end of the endless belt as compared with the case where there is no lubricant holding portion. In addition, an effect of reducing leakage of lubricating oil from the belt end can be obtained.

  Also, the amount of lubricant (lubricating oil) supplied to reduce the sliding resistance between the pressing member and the belt inner surface is small in the belt, or a lubricant with low fluidity such as grease is used. In some cases, the lubricant hardly wraps around the belt end. In that case, it is possible to keep the sliding resistance with the belt guide sliding surface low for a long period of time by filling and holding the lubricant in the lubricant holding portion in advance and using the lubricant. It becomes possible. As a result, it is possible to effectively prevent the occurrence of cracking that leads to wear deformation and belt breakage at the end of the endless belt as compared with the case where there is no holding portion for the lubricant.

(Lubricant holding part)
The lubricant holding portion provided at the end of the belt main body in the present invention will be described.
Here, the “end portion of the belt main body” where the lubricant holding portion is provided refers to a range from the edges of both ends of the belt main body to 20 mm in the belt axial direction.
As shown in FIGS. 1 to 3, the lubricant holding portion in the present invention does not need to be provided so as to contact the edge of the belt body, but may be provided within the range of the end portion. Considering that the end face of the belt body hits the meandering prevention member due to the endless belt walk, the higher the end face of the endless belt, the better the strength of the end face of the end belt. It is preferable to be provided.
Further, the lubricant holding portion need not be provided over the entire circumference of the end portion of the belt body, and may be provided intermittently along the end portion of the belt body. From the viewpoint of the strength and ease of manufacture, it is preferably provided continuously over the entire circumference of the end of the belt body. When the lubricant holding portion is provided intermittently, the ratio of the lubricant holding portion to the entire circumference of the end of the belt body is at least 50% or more of the entire circumference from the viewpoint of securing the lubricant holding performance. It is preferable that
Furthermore, although the lubricant holding portion in the present invention may be provided only at one end portion of the belt body, it is preferable to provide the lubricant holding portion at both end portions from the viewpoint of more efficiently achieving the effects of the present invention.

As shown in FIGS. 1 and 2, when the lubricant holder in the present invention is configured to include a porous body, the size of the porous body is not particularly limited, The length in the belt axis direction (L in FIGS. 1 and 2) may be determined as appropriate depending on whether it is provided on the peripheral surface side or on the outer peripheral surface side. 1-10 mm is preferable, 3-5 mm is more preferable, and the thickness (T in FIGS. 1 and 2) is preferably 0.1-2 mm, and more preferably 0.2-1 mm.
In addition, as shown in FIG.1 and FIG.2, it is preferable that the lubricant holding | maintenance part comprised including such a porous body is provided so that the edge of a belt main body may be contact | connected.

  When the lubricant holding part in the present invention is composed of a porous body and a reinforcing member, the reinforcing member preferably covers a part of the surface of the porous body as long as the lubricant holding function is not impaired. . Since the site | part close | similar to the end surface of the belt main body of a porous body is a location where a lubricant retention function expresses most effectively, it is preferable to cover the surface other than this location with a reinforcing member. For example, as shown in FIG. 2, when the porous body is provided from the edge of the belt body, the reinforcing member covers a portion other than the end face of the porous body that is continuous with the end face of the belt body. Preferably there is. By adopting such a configuration, the lubricant holding function is expressed on the exposed end surface of the porous body, and the porous body is peeled off or deformed due to the presence of the reinforcing member in other portions. Can be prevented.

Further, as shown in FIG. 3, when the lubricant holding portion in the present invention is a groove that opens outward in parallel to the belt axis direction along the circumferential direction of the end surface of the belt body, The size is not particularly limited and may be appropriately determined depending on whether it is provided on the inner peripheral surface side or the outer peripheral surface side of the belt body. Groove depth: D) in FIG. 3 is preferably 0.5 to 8 mm, more preferably 1 to 4 mm. The width viewed from the belt diameter direction (height of the groove: H in FIG. 3) is preferably 0.1 mm to 2 mm, more preferably 0.2 mm to 1 mm.
Further, it is not necessary that all the concave grooves are continuously opened along the circumferential direction of the belt main body, and the concave grooves may be discontinuous.

Further, as shown in FIG. 2, a lubricant holding portion composed of a porous body and a reinforcing member, and a lubricant holding portion having a concave groove as shown in FIG. It can also be provided on the peripheral surface side.
The lubricant retaining portion in the present invention is preferably provided on the outer peripheral surface side of the belt body from the viewpoint of ease of manufacture and durability against sliding with the meandering prevention member.
On the other hand, the lubricant holding portion in the present invention is preferably provided on the inner peripheral surface side of the belt body from the viewpoint that the lubricant can be reliably prevented from moving to the outer peripheral surface of the belt.

In addition, the belt main body is provided with a lubricant holding portion having a concave groove on the outer peripheral surface side or the inner peripheral surface side of the belt main body, and further, a holding portion made of a porous body is provided on the outer peripheral surface side of the belt main body. It is also possible to laminate.
Furthermore, in the lubricant holding part having a concave groove, a porous body may be embedded in the concave groove in order to further improve the retention of the low viscosity lubricant. Further, a lubricant may be held in advance in the concave groove.

The lubricant holding part in the present invention can be provided as follows.
For example, as shown in FIG. 1 and FIG. 2, when the lubricant holding portion is made of a porous body, a tape-shaped or ring-shaped porous body processed to a predetermined thickness is used as an adhesive or the like. It can be manufactured by bonding to the end of the belt body with the bonding agent, or if the surface layer of the belt body is a thermoplastic resin, bonding by thermocompression bonding.

  As shown in FIG. 2, when the lubricant holding part is composed of a porous body and a reinforcing member for reinforcing the porous body, the porous body joined in advance by the above method It is possible to manufacture by winding a tape-like sheet around the surface of the material, or coating a ring-shaped reinforcing member.

  In addition, as shown in FIG. 3, when the lubricant holding portion is formed of a concave groove that opens outward in parallel to the belt axial direction along the circumferential direction of the belt end face, Wrap the sheet around the end of the belt body, or insert a short ring-shaped concave groove forming member having an inner diameter larger than the outer diameter of the belt main body into the end of the belt body, and the gap portion that becomes the concave groove It is possible to bond by adhering to the end of the belt body using a bonding agent, or by welding if the material is a thermoplastic resin.

Also, when a groove is provided on the inner side of the belt, a tape-shaped sheet is wound around the end of the belt body, or a ring-shaped groove forming member having a short outer diameter smaller than the inner diameter of the belt body is used as the belt body. In the same manner as in the case of being provided on the outer side of the belt main body, it can be manufactured by leaving a gap portion to be a concave groove and joining with a bonding agent or heat welding.
However, when manufacturing a lubricant holding portion having a concave groove, it is preferable to use a seamless endless ring-shaped member as the concave groove forming member from the viewpoint of durability.

As the porous body constituting the lubricant holding portion in the present invention, any porous material having heat resistance can be used. Felt, non-woven fabric, woven fabric, knitted fabric, foamable material, porous sintering A conventionally known porous tissue material such as a body can be used. Specifically, for example, felt made of wholly aromatic polyamide resin (aramid resin) fiber, non-porous polytetrafluoroethylene (PTFE) fiber, porous PTFE fiber, tetrafluoroethylene perfluoroalkyl vinyl ether (PFA) Fluororesin fibers such as fibers, tetrafluoroethylene hexafluoropropylene (FEP) fibers, polyethylenetetrafluoroethylene (ETFE) fibers, and combinations of these fluorinated resin fibers, or these fluorinated resin fibers and other organic fibers Or a combination of inorganic fibers as appropriate. A foam made of polyimide resin or melamine resin can also be used.
These porous bodies can also be used as those embedded in the concave grooves.

As the groove forming member and the reinforcing member constituting the lubricant holding portion in the present invention, the same material as the base layer of the belt main body can be used, and those of various known plastic materials and metal materials can be used. It can be used by appropriately selecting from among them.
Among plastic materials, what is generally called engineering plastics is suitable. For example, fluororesin, polyimide (PI), polyamideimide (PAI), polybenzimidazole (PBI), polyetheretherketone (PEEK), polysulfone ( PSU), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetherimide (PEI), wholly aromatic polyester (liquid crystal polymer) and the like are preferable.
Of these, thermosetting polyimide, thermoplastic polyimide, polyamideimide, polyetherimide, fluororesin, etc., which are excellent in mechanical strength, heat resistance, wear resistance, chemical resistance and the like are preferable.
Moreover, there is no restriction | limiting in particular as a metal material, Various metals can be used suitably, For example, SUS, nickel, copper, aluminum etc. can be used conveniently.
In addition, it is also possible to laminate | stack the said various resin and various metals. Further, various fillers can be added in the same manner as the base layer of the belt body described later.

  In the present invention, various adhesives and various unvulcanized rubbers may be used as the bonding agent for bonding the porous body, the reinforcing member, the concave groove forming member, and the belt body (or the porous body) constituting the lubricant holding portion. Various thermosetting resins and various thermoplastic resins can be used. Moreover, what demonstrates adhesiveness by a heating or pressurization needs to heat and pressurize as needed after filling the clearance gap of a junction part. In addition, in a thermoplastic resin or the like, heat fusion (ultrasonic fusion) can be performed by applying ultrasonic vibration under pressure.

  Examples of the adhesive include a condensation curable or addition curable silicone adhesive mainly composed of organopolysiloxane, and a modified silicone adhesive mainly composed of polypropylene oxide (modified silicone) terminated with a methyldimethoxysilyl group. Agents, polyimide adhesives based on polyimide (PI) low molecular weight polymers belonging to aromatic heterocyclic polymers, and polybenzimidazoles (PBI) based on polybenzimidazole belonging to aromatic heterocyclic polymers Imidasol adhesive, epoxy resin based epoxy resin, urethane resin adhesive, reactive hot melt adhesive, polyurethane resin hot melt adhesive, polyamide resin hot melt adhesive, polyolefin resin hot melt adhesive Agents, chloroprene rubber adhesives, etc. From the viewpoint of heat resistance and flexibility, silicone and modified silicone or polyimide are preferred.

  In addition, various fillers can be added to the filler formed as the joint for the purpose of ensuring durability and conductivity. As the filler, a lubricious filler having a layered structure (eg, molybdenum disulfide, hexagonal boron nitride, mica, graphite, molybdenum disulfide, talc), conductive filler (eg, carbon black, graphite), heat resistance Filler comprising a heat-resistant resin (for example, a filler in which the heat-resistant resin is selected from imide resin, amide resin, and wholly aromatic polyester resin: polyimide, liquid crystal polymer, aramid), and others (glass powder) , Aluminum silicate, carbon fiber, bronze, potassium titanate, titanium oxide, metal powder, barium sulfate, metal oxide, carbide, nitride, silicate compound) and the like can be used.

  Moreover, as the thermoplastic resin as the bonding agent, various commercially available thermoplastic resins can be used. However, in consideration of heat resistance, various fluororesins, thermoplastic polyimide (PI), polyamideimide (PAI), poly Ether imide (PEI) is suitable.

In the present invention, as described above, in the case of a lubricant holding part having a concave groove, the concave groove can be filled with a lubricant in advance.
As the lubricant used in this case, silicone oil is preferable. Specific examples of the silicone oil include dimethyl silicone oil, dimethyl silicone oil with addition of organometallic salt, hindered amine addition dimethyl silicone oil, organometallic salt and hindered amine addition dimethyl. Silicone oil, methylphenyl silicone oil, amino-modified silicone oil, amino-modified silicone oil added with organic metal salt, hindered amine-added amino-modified silicone oil, carboxy-modified silicone oil, silanol-modified silicone oil, sulfonic acid-modified silicone oil, etc. can also be used. However, an amino-modified silicone oil superior in wettability is more preferable.
In addition, when superior performance due to heat resistance is required, it is also preferable to use methylphenyl silicone oil or fluorine oil (perfluoropolyether oil, modified perfluoropolyether oil) or the like. In addition, in order to improve heat resistance, it is also possible to add a trace amount antioxidant in silicone oil.
In addition, synthetic lubricating oil grease in which a solid substance and a liquid are mixed, for example, silicone grease, fluorine grease, or the like, or a combination thereof can also be used.

(Belt body)
As described above, the belt body constituting the endless belt of the present invention may have a single-layer structure composed of only a base layer, or an arbitrary layer (for example, a coating layer containing a thermoplastic resin) on the base layer. A multilayer structure having

The material used for the base layer of the belt body in the present invention is not particularly limited, but can be appropriately selected from known plastic materials and metal materials.
Among plastic materials, what is generally called engineering plastic is suitable. For example, fluororesin, polyimide (PI), polyamideimide (PAI), polybenzimidazole (PBI), polyetheretherketone (PEEK), polysulfone (PSU), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetherimide (PEI), wholly aromatic polyester (liquid crystal polymer) and the like are preferable. Of these, thermosetting polyimide, thermoplastic polyimide, polyamideimide, polyetherimide, fluororesin and the like, which are excellent in mechanical strength, heat resistance, wear resistance, chemical resistance, and the like, are preferable.
Moreover, there is no restriction | limiting in particular as a metal material, Various metals can be used suitably, For example, SUS, nickel, copper, aluminum etc. can be used conveniently.
In addition, it is also possible to laminate | stack the said various resin and various metals.
The thickness of the base layer in the belt main body is preferably in the range of 20 to 200 μm, and more preferably in the range of 40 to 100 μm.

In the belt body of the present invention, a rubber material can be laminated on the entire surface or a part of the base layer. The rubber material can be used as appropriate from various rubber materials, and examples thereof include urethane rubber, ethylene / propylene rubber (EPM), silicone rubber, fluoro rubber (FKM), and the like. Silicone rubber having excellent processability is preferred.
The thickness of the rubber material is preferably in the range of 30 to 500 μm, and more preferably in the range of 100 to 300 μm.

Furthermore, when the endless belt of the present invention is used as a fixing belt, the belt main body is preferably laminated with a non-adhesive fluororesin on the outermost surface layer as a surface release layer. Examples of the fluororesin include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), and tetrafluoroethylene-perfluoroethyl vinyl ether copolymer ( EFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychloroethylene trifluoride (PCTFE), Fluorine resins such as vinyl fluoride (PVF) are mentioned, and polytetrafluoroethylene (PTFE) and tetrafluoroethylene-perfluoroalkyl vinyl are particularly preferred from the viewpoints of heat resistance and mechanical properties. Ether copolymer (PFA) of tetrafluoroethylene - perfluoro methyl vinyl ether copolymer (MFA), tetrafluoroethylene - perfluoro ethyl vinyl ether (EFA) copolymer or their modified products are preferably used.
The thickness of the surface release layer is preferably in the range of 5 to 100 μm, and more preferably in the range of 10 to 50 μm.

Various fillers can be appropriately added to each layer constituting the belt body in the present invention according to the purposes such as conductivity, thermal conductivity, insulation, peelability, slidability and reinforcement.
As the filler, a lubricating filler having a layered structure (eg, molybdenum disulfide, hexagonal boron nitride, mica, graphite, molybdenum disulfide disulfide, talc), conductive filler (eg, carbon black, graphite) , A filler comprising a heat-resistant resin (for example, a filler in which the heat-resistant resin is selected from an imide resin, an amide resin, and a wholly aromatic polyester resin: for example, polyimide, liquid crystal polymer, aramid), and others ( Glass powder, aluminum silicate, carbon fiber, bronze, potassium titanate, titanium oxide, metal powder, barium sulfate, metal oxide, carbide, nitride, silicate compound) and the like can be used.

  In the belt of the present invention, a lubricant holding portion is provided on one or both ends of a single-layer structure or a multilayer structure belt body, and further, various heat-resistant resins such as fluororesin and various metals are provided thereon. Alternatively, a plurality of various rubber materials can be laminated.

<Fixing device>
Next, the fixing device of the present invention using the endless belt of the present invention will be described.
FIG. 4 is a schematic cross-sectional view showing an embodiment of the fixing device of the present invention.
In the fixing device 30 shown in FIG. 4, 31 is a heat fixing roll, 32 is an endless belt, 33 is a recording medium, 34 is a heating source, 35 is a support, 36 is a pressing member, 36a is a pre-nip member, and 36b is a peeling nip member. 37 is a sliding sheet member, 38 is a belt guide, 39 is a toner image, and 40 is a lubricant holding member. In the fixing device 30, the endless belt 32 is the endless belt of the present invention, and has the above-described effects such as high durability.

A fixing device 30 shown in FIG. 4 has an endless belt 32 circumscribed on a drive-type heat-fixing roll 31, and an elastic body is mounted on a support 35 with respect to the endless belt 32 portion of the circumscribed portion, and a sliding sheet member The pressing member 36 covered 37 is inscribed, and a pressure contact region (nip portion) is formed between the heat fixing roll 31 and the endless belt 32. Lubricant is interposed on the sliding contact surface with respect to the endless belt 32, and the lubricant supplied to the inner peripheral surface of the endless belt 32 is rotated and supplied to the sliding contact surface side of the press contact area. Further, the heat fixing roll 31 and the endless belt 32 are heated to a predetermined temperature by the heating source 34, and each rotate in the direction of the arrow. The toner image is fixed while the recording medium 33 having the toner image 39 passes through the nip portion.
The belt guide 38 having the lubricant holding member 40 is fixed to the support 35, and the endless belt 32 smoothly slides and rotates by the belt guide 38.

Hereinafter, members other than the endless belt used in the fixing device of the present embodiment will be described.
The heat fixing roll as the fixing member is not particularly limited with respect to its shape, structure, size and the like, and can be appropriately selected from those known per se according to the purpose. Generally, the heat fixing roll includes a cylindrical core, an elastic layer formed on the surface thereof, and a release layer formed on the surface of the elastic layer. This heat fixing roll can be manufactured by a known manufacturing method. Generally, a mold for forming an elastic layer is disposed around a cylindrical core, and liquid rubber is formed between the mold and the cylindrical roll. After being poured into the gap between the cores, vulcanized and hardened, and a resin sleeve such as PFA on the surface can be used.

  The material of the cylindrical core is not particularly limited as long as the material has excellent mechanical strength and good heat transfer properties. For example, metals such as aluminum, SUS, iron and copper, alloys, ceramics, FRM, etc. Is mentioned.

  The material of the elastic layer can be appropriately selected from known materials for the elastic layer, and examples thereof include silicone rubber and fluorine rubber. In the present invention, among these materials, silicone rubber is preferable because it has a small surface tension and is excellent in elasticity. Examples of the silicone rubber include RTV silicone rubber and HTV silicone rubber. Specifically, polydimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ), fluoro Examples include silicone rubber (FVMQ).

  The thickness of the elastic layer is preferably 3 mm or less, and more preferably in the range of 0.5 to 1.5 mm.

  A release layer is preferably formed on the surface of the elastic layer from the viewpoint that the offset of the toner image can be suitably prevented. The material of the release layer is not particularly limited as long as it exhibits an appropriate release property with respect to the toner image, and examples thereof include fluorine rubber, silicone rubber, and fluorine resin. Among these materials, a fluororesin is preferable.

  Examples of the fluororesin include, for example, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), tetrafluoroethylene-perfluoroethyl vinyl ether copolymer ( EFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychloroethylene trifluoride (PCTFE), Fluorine resin such as vinyl fluoride (PVF) can be used.

  In particular, from the viewpoints of heat resistance, mechanical properties, etc., polytetrafluoroethylene (PTFE), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), A tetrafluoroethylene-perfluoroethyl vinyl ether (EFA) copolymer is preferably used.

  As a thickness of a mold release layer, it is 10-100 micrometers normally, Preferably it is 20-30 micrometers. There is no restriction | limiting in particular as a method of forming the said mold release layer in the surface of the said elastic layer, For example, the method of coat | covering the tube formed by extrusion molding is mentioned.

The heat source is not particularly limited as long as it has a shape and structure that can be accommodated in the core using, for example, a halogen lamp, and can be appropriately selected according to the purpose. The surface temperature of the heat fixing roll heated by the halogen lamp is measured by a temperature sensitive element provided on the heat fixing roll, and the temperature is controlled to be constant by the control means. There is no restriction | limiting in particular as a temperature sensing element, For example, a thermistor, a temperature sensor, etc. are mentioned.
Further, the pressing member may have a resistance heating mechanism.

  As the pressing member, an elastic body (pre-nip member) is mounted on the support, and is disposed inside the endless belt and presses the heat fixing roll via the endless belt, and between the endless belt and the heat fixing roll, There is no particular limitation as long as it has a function capable of forming a pressure contact portion (nip portion) through which a recording sheet holding an unfixed toner image can pass, and it can be appropriately selected from known ones according to the purpose. From the viewpoint of preventing deterioration due to heat at the time of fixing, it is preferable to use a material having heat resistance.

  As the material of the elastic body, heat-resistant elastomers such as silicone rubber and fluororubber are suitable, and among these materials, silicone rubber is preferable in terms of excellent elasticity. Examples of the silicone rubber include RTV silicone rubber and HTV silicone rubber. Specifically, polydimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ), fluoro Examples include silicone rubber (FVMQ). From the viewpoint of hardness, silicone rubber having a JIS-A hardness of 10 to 40 ° is preferably used.

There is no restriction | limiting in particular about the shape, structure, size, etc. of an elastic body (pre-nip member), and it can select suitably according to the objective. The pressing member may have a structure composed of a single member or a structure composed of a plurality of members having different functions. When silicone oil is used as the sliding oil, polydimethyl silicone rubber or methyl vinyl silicone rubber is easily swelled by silicone oil, and it is necessary to coat the surface of the elastic body with a fluororesin or the like.
In addition to the elastic body, the pressing member may have a peeling nip member that protrudes from the outer peripheral surface side of the heat fixing roller. Further, the pressing member (pre-nip member) is not necessarily an elastic body, and may be a heat-resistant resin or a metal.

  Further, as a sliding member (sliding sheet member) interposed between the pressing member and the endless belt, at least a contact surface side with the endless belt is formed of a fluororesin having a concavo-convex shape on the surface. This uneven shape holds the lubricant.

  Silicone oil is preferable as the lubricant provided between the pressing member and the endless belt. Specific examples of the silicone oil include dimethyl silicone oil, dimethyl silicone oil with an organic metal salt, dimethyl silicone oil with a hindered amine, dimethyl silicone oil with an organic metal salt and a hindered amine, methyl phenyl silicone oil, amino-modified silicone oil, and organic metal. A salt-added amino-modified silicone oil, a hindered amine-added amino-modified silicone oil, a carboxy-modified silicone oil, a silanol-modified silicone oil, a sulfonic acid-modified silicone oil, and the like can be used, but an amino-modified silicone oil having excellent wettability is more preferable. In addition, when superior performance due to heat resistance is required, it is also preferable to use methylphenyl silicone oil or fluorine oil (perfluoropolyether oil, modified perfluoropolyether oil) or the like. In addition, in order to improve heat resistance, it is also possible to add a trace amount antioxidant in silicone oil. In addition, synthetic lubricant grease in which a solid substance and a liquid are mixed, for example, silicone grease, fluorine grease, and the like, or a combination thereof can also be used.

  A belt guide is attached to the support so as to make the endless belt slide and rotate smoothly. The belt guide is provided with a lubricant holding member, and the lubricant is held by the lubricant holding member.

Furthermore, it is preferable that the fixing device of the present invention is provided with a meandering prevention member that contacts the end face of the endless belt and prevents the meandering. The meandering prevention member will be described with reference to FIG. Here, FIGS. 5A and 5B are schematic views showing the configuration of the meandering prevention member provided in the fixing device of the present invention.
According to FIGS. 5A and 5B, the meandering prevention member 90 includes a support portion 92, a flange portion 94, and an insertion portion 96. As shown in FIG. 5A, the meandering prevention member 90 has its insertion part 90 inserted from both ends of the endless belt (endless belt shown in FIG. 1), and the endless belt meandered the flange part 94. At this time, they are arranged in a state where they are separated by a certain distance so as to abut against the end face. At this time, the endless belt is configured to rotate along the outer peripheral surface of the belt guide 38. As shown in FIG. 4, the endless belt is configured to be pressed against the heat fixing roll 31 by the pressing member 36, so that it is driven and rotated by the frictional force from the heat fixing roll 31 due to the pressing force. . As a result, if the frictional force from the heat-fixing roll becomes uneven in the width direction due to variations in part dimensions or the paper that passes through the nip, the endless belt will not be able to move in the width direction. A so-called belt walk occurs that works and moves to either end. Therefore, in the fixing device of the present invention, the meandering prevention member 90 as shown in FIG. 5 is provided, and the meandering of the endless belt is limited by the flange portion 94 provided so that the end of the endless belt abuts. It is possible to regulate the deviation of the endless belt.
The meandering prevention member is formed of a heat-resistant resin such as PPS, PET, PBT, or LCP, and further added with a filler for lowering durability and a friction coefficient.

<Image forming apparatus>
Next, the image forming apparatus of the present invention provided with the fixing device of the present invention will be described.
FIG. 6 is a schematic configuration diagram showing an embodiment of the image forming apparatus of the present invention. The image forming apparatus shown in FIG. 6 is an intermediate transfer type image forming apparatus generally called a tandem type, and a plurality of image forming units 1Y, 1M, and 1C in which toner images of respective color components are formed by electrophotography. , 1K, the respective color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 45, the primary transfer unit 40 that sequentially transfers (primary transfer) to the intermediate transfer belt 45. A secondary transfer unit 50 that collectively transfers (secondary transfer) the superimposed toner image onto a sheet P that is a recording medium, and a fixing device 30 that fixes the secondary transferred image onto the sheet P are provided. The fixing device 30 is the fixing device of the present invention described above, and the fixing device includes the endless belt of the present invention described above. Therefore, the image forming apparatus has the above-described effects such as high durability.
Moreover, it has the control part 70 which controls operation | movement of each apparatus (each part).

  In the present embodiment, each of the image forming units 1Y, 1M, 1C, and 1K includes a charger 42 that charges the photosensitive drum 41 around the photosensitive drum 41 that rotates in the direction of arrow A, and a photosensitive member. A laser exposure unit 43 in which an electrostatic latent image is written on the drum 41 (exposure beam is indicated by a symbol Bm in the drawing), each color component toner is accommodated, and the electrostatic latent image on the photosensitive drum 41 is visible with the toner. The developing unit 44 that forms an image, the primary transfer roll 46 that transfers each color component toner image formed on the photosensitive drum 41 to the intermediate transfer belt 45 by the primary transfer unit 40, and the residual toner on the photosensitive drum 41 are removed. The electrophotographic devices such as the drum cleaner 47 are sequentially arranged. These image forming units 1Y, 1M, 1C, and 1K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 45. Has been.

The intermediate transfer belt 45, which is an intermediate transfer body, is composed of a film-like endless belt in which an appropriate amount of an antistatic agent such as carbon black is contained in a resin such as polyimide or polyamide. And the volume resistivity is formed so that it may become 10 < ⁶ > -10 < ¹⁴ > (omega | ohm) cm, The thickness is comprised by about 0.1 mm, for example. The intermediate transfer belt 45 is circulated and driven at various speeds in the direction B shown in FIG. 6 by various rolls. As these various rolls, a drive roll 61 that is driven by a motor (not shown) having excellent constant speed and rotates the intermediate transfer belt 45, and an intermediate transfer that extends substantially linearly along the arrangement direction of the photosensitive drums 41. A support roll 62 that supports the belt 45, a tension roll 63 that functions as a correction roll that applies a constant tension to the intermediate transfer belt 45 and prevents the intermediate transfer belt 45 from meandering, and a backup roll provided in the secondary transfer unit 50 55, a cleaning backup roll 64 provided in a cleaning unit that scrapes off residual toner on the intermediate transfer belt 45.

The primary transfer unit 40 includes a primary transfer roll 46 that is disposed to face the photosensitive drum 41 with the intermediate transfer belt 45 interposed therebetween. The primary transfer roll 46 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ^7.5 to 10 ^8.5 Ωcm. The primary transfer roll 46 is disposed in pressure contact with the photosensitive drum 41 with the intermediate transfer belt interposed therebetween. Further, the primary transfer roll 46 has a voltage (a negative polarity; the same applies hereinafter) having a polarity opposite to that of the toner. (Primary transfer bias) is applied. As a result, the toner images on the respective photosensitive drums 41 are sequentially electrostatically attracted to the intermediate transfer belt 45, and the superimposed toner images are formed on the intermediate transfer belt 45.

The secondary transfer unit 50 includes a secondary transfer roll 52 disposed on the toner image holding surface side of the intermediate transfer belt 45 and a backup roll 55. The backup roll 55 is composed of a tube of EPDM and NBR blend rubber with carbon dispersed on the surface, and EPDM rubber inside. And it is formed so that the surface resistivity may be 10 ⁷ to 10 ¹⁰ Ω / □, and the hardness is set to, for example, 70 ° (Asker C: manufactured by Kobunshi Keiki Co., Ltd., the same shall apply hereinafter). The backup roll 55 is disposed on the back side of the intermediate transfer belt 45 to form a counter electrode of the secondary transfer roll 52, and a metal power supply roll 56 to which a secondary transfer bias is stably applied is disposed in contact with the backup roll 55. Yes.

On the other hand, the secondary transfer roll 52 includes a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR and EPDM containing a conductive agent such as carbon black and having a volume resistivity of 10 ^7.5 to 10 ^8.5 Ωcm. The secondary transfer roll 52 is placed in pressure contact with the backup roll 55 with the intermediate transfer belt 45 interposed therebetween. Further, the secondary transfer roll 52 is grounded, and a secondary transfer bias is formed between the secondary transfer roll 52 and the backup roll 55. The toner image is secondarily transferred onto the paper P conveyed to the next transfer unit 50.

  Further, on the downstream side of the secondary transfer portion 50 of the intermediate transfer belt 45, an intermediate transfer belt that removes residual toner and paper dust on the intermediate transfer belt 45 after the secondary transfer and cleans the surface of the intermediate transfer belt 45. A cleaner 65 is provided so as to be able to contact and separate. On the other hand, on the upstream side of the yellow image forming unit Y, a reference sensor (home position sensor) 72 that generates a reference signal serving as a reference for taking image forming timings in the image forming units Y, M, C, and K is provided. It is arranged. Further, an image density sensor 73 for adjusting image quality is disposed on the downstream side of the black image forming unit K. The reference sensor 72 recognizes a predetermined mark provided on the back side of the intermediate transfer belt 45 and generates a reference signal. Each image forming unit is instructed by an instruction from the control unit 70 based on the recognition of the reference signal. 1Y, 1M, 1C, and 1K are configured to start image formation.

  Furthermore, in the image forming apparatus of the present embodiment, as a paper transport system, a paper tray 80 that stores paper P, a pick-up roll 81 that picks up and transports the paper P accumulated in the paper tray 80 at a predetermined timing, and a pick-up roll The second transfer is performed by the secondary transfer roll 52, the transport roll 82 for transporting the paper P fed out at 81, the transport path 83 for feeding the paper P transported by the transport roll 82 to the secondary transfer unit 50. A conveyance belt 85 that conveys the sheet P to be conveyed later to the fixing device 30 and a fixing entrance guide 86 that guides the sheet P to the fixing device 30 are provided.

  Next, a basic image forming process of the image forming apparatus according to the present embodiment will be described. In the image forming apparatus as shown in FIG. 6, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is subjected to predetermined image processing by an image processing device (not shown), Image forming work is executed by the image forming units 1Y, 1M, 1C, and 1K. The image processing apparatus performs predetermined image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and other various image editing on the input reflectance data. Is given. The image data subjected to the image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure device.

  The laser exposure unit 43 irradiates, for example, an exposure beam Bm emitted from a semiconductor laser to the photosensitive drums 41 of the image forming units 1Y, 1M, 1C, and 1K according to the input color material gradation data. ing. In each of the photosensitive drums 41 of the image forming units 1Y, 1M, 1C, and 1K, after the surface is charged by the charger 42, the surface is scanned and exposed by the laser exposure unit 43 to form an electrostatic latent image. The formed electrostatic latent image is developed as a toner image of each color of Y, M, C, and K in each of the image forming units 1Y, 1M, 1C, and 1K.

  The toner images formed on the photosensitive drums 41 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 45 at the primary transfer unit 40 where the photosensitive drums 41 and the intermediate transfer belt 45 are in contact with each other. Is transcribed. More specifically, in the primary transfer unit 40, a voltage (primary transfer bias) having a polarity opposite to the charging polarity (minus polarity) of the toner is applied to the base material of the intermediate transfer belt 45 by the primary transfer roll 46. Primary transfer is performed by sequentially superimposing images on the surface of the intermediate transfer belt 45.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 45, the intermediate transfer belt 45 moves and the toner image is conveyed to the secondary transfer unit 50. When the toner image is transported to the secondary transfer unit 50, in the paper transport system, the pick-up roll 81 rotates in accordance with the timing at which the toner image is transported to the secondary transfer unit 50, and the paper of a predetermined size is transferred from the paper tray 80. P is supplied. The paper P supplied by the pickup roll 81 is transported by the transport roll 82, and reaches the secondary transfer unit 50 through the transport path 83. Before reaching the secondary transfer unit 50, the paper P is temporarily stopped, and a registration roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 45 on which the toner image is held. And the position of the toner image are aligned.

  In the secondary transfer unit 50, the secondary transfer roll 52 is pressed against the backup roll 55 via the intermediate transfer belt 45. At this time, the sheet P conveyed at the same timing is sandwiched between the intermediate transfer belt 45 and the secondary transfer roll 52. At this time, when a voltage (secondary transfer bias) having the same polarity as the charging polarity (negative polarity) of the toner is applied from the power supply roll 56, a transfer electric field is formed between the secondary transfer roll 52 and the backup roll 55. Is done. The unfixed toner image held on the intermediate transfer belt 45 is collectively electrostatically transferred onto the paper P by the secondary transfer unit 50 pressed by the secondary transfer roll 52 and the backup roll 55. The

  Thereafter, the sheet P on which the toner image has been electrostatically transferred is transported as it is while being peeled off from the intermediate transfer belt 45 by the secondary transfer roll 52, and transported downstream of the secondary transfer roll 52 in the sheet transport direction. It is conveyed to the belt 85. The conveyance belt 85 conveys the paper P to the fixing device 30 in accordance with the optimum conveyance speed in the fixing device 30. The unfixed toner image on the paper P conveyed to the fixing device 30 is fixed on the paper P by being subjected to a fixing process by heat and pressure by the fixing device 30. Then, the paper P on which the fixed image is formed is conveyed to a discharge unit of the image forming apparatus.

  On the other hand, after the transfer to the paper P is completed, the residual toner remaining on the intermediate transfer belt 45 is conveyed to the cleaning unit as the intermediate transfer belt 45 rotates, and is cleaned by the cleaning backup roll 64 and the intermediate transfer belt cleaner 65. The intermediate transfer belt 45 is removed.

  Although the embodiment of the present invention has been described above, the present invention is not construed as being limited to the above-described embodiment, and it is needless to say that the present invention can be realized within a range that satisfies the requirements of the present invention.

  In the following, an endless belt of the present invention (Example) and a conventional endless belt having no lubricant holding portion at the end of the belt body as a comparative example were produced and attached to the fixing device and the image forming apparatus. The evaluation result at the time will be specifically described. However, the present invention is not limited to the following examples.

(Example 1)
First, N-methylpyrrolidone solution of polyimide precursor (trade name: U Varnish, manufactured by Ube Industries, Ltd.) is flow-coated (spiral wound) on the surface of an aluminum cylindrical mold having an outer diameter of 30 mm subjected to blast treatment. After coating with a coating method and spin-drying, a fluororesin (PFA) dispersion solution (trade name: 710CL, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) is coated by spray coating, and then a coating film is formed at 380 ° C. Baked. Next, the formed film is removed from the core surface, and both ends are cut, and a coating layer having a film thickness of 25 μm containing PFA as a thermoplastic resin is formed on the outer periphery of a polyimide resin (heat-resistant resin) having a film thickness of 70 μm. A formed belt body having a total length of 352 mm was obtained.

Next, a 12 μm-thick FEP film (Neoflon NF manufactured by Daikin Industries, Ltd.) is formed on the woven fabric surface of a laminate (Japan Gore-Tex, product number # 8181) of a stretched porous PTFE film and a woven fabric made of porous PTFE fibers. A sheet having a width of 5 mm and a length of 94.5 mm was cut out from a sheet having a thickness of 300 μm obtained by thermocompression bonding of -0012). This sheet is stacked on both ends of the outer peripheral surface of the belt body so that the FEP film surface side is in contact with the coating layer of the belt body (coating layer containing PFA), and is pressed while heating to about 300 ° C. The lubricant holding part comprised from this was formed.
As a result, an endless belt provided with the lubricant holding portion 20a composed of the porous body 22 as shown in FIG. 1 was obtained. The length of the formed porous body in the belt axis direction (L in FIG. 1) is 5 mm, and the thickness (T in FIG. 1) is 300 μm.

(Example 2)
First, N-methylpyrrolidone solution of polyimide precursor (trade name: U Varnish, manufactured by Ube Industries, Ltd.) is flow-coated (spiral wound) on the surface of an aluminum cylindrical mold having an outer diameter of 30 mm subjected to blast treatment. After coating with a coating method and spin-drying, a fluororesin (PFA) dispersion solution (trade name: 710CL, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) is coated by spray coating, and then a coating film is formed at 380 ° C. Baked. Next, the formed film is removed from the core surface, and both ends are cut, and a coating layer having a film thickness of 25 μm containing PFA as a thermoplastic resin is formed on the outer periphery of a polyimide resin (heat-resistant resin) having a film thickness of 70 μm. A formed belt body having a total length of 352 mm was obtained.

Next, a 12 μm-thick FEP film (Neoflon NF manufactured by Daikin Industries, Ltd.) is formed on the woven fabric surface of a laminate (Japan Gore-Tex, product number # 8181) of a stretched porous PTFE film and a woven fabric made of porous PTFE fibers. A sheet having a width of 5 mm and a length of 94.5 mm was cut out from a sheet having a thickness of 300 μm obtained by thermocompression bonding of -0012). This sheet was overlapped at both ends of the outer peripheral surface of the belt main body so that the FEP film surface side was in contact with the coating layer (coating layer containing PFA) of the belt main body, and was pressure-bonded while being heated to about 300 ° C.
After that, as a reinforcing member, 0.2 mm thick and 32 mm inner diameter FEP heat-shrinkable tube (general-purpose commercial product) is cut into a length of 10 mm and inserted into both ends of the belt body provided with the porous body as described above. Further, hot air at 200 ° C. was blown to shrink the FEP tube, and the porous body was covered with a reinforcing member.
As a result, an endless belt provided with the lubricant holding portion 20b composed of the porous body 22 and the reinforcing member 24 as shown in FIG. 2 was obtained. In addition, the length (L in FIG. 2) of the formed porous body in the belt axial direction is 5 mm, and the thickness (T in FIG. 2) is 300 μm.

(Example 3)
First, an N-methylpyrrolidone solution of a polyimide precursor (trade name: U Varnish, Ube Industries, Ltd.) is applied to the surface of an aluminum cylindrical mold having an outer diameter of 30 mm that has been blasted on the surface by a flow coating method. And spin-dried. Next, the part other than the central part 336 mm of the polyimide-coated mold was masked, and further, a fluororesin (PFA) dispersion (trade name: 710CL, manufactured by Mitsui / DuPont Fluorochemical Co., Ltd.) was coated by spray coating, and then at 380 ° C. The coating was baked. Thereafter, the formed film is removed from the core surface, and both ends are cut, and a coating layer having a film thickness of 25 μm containing PFA as a thermoplastic resin is formed on the outer periphery of the polyimide resin having a film thickness of 70 μm. A belt main body formed only in the central portion 336 mm was obtained.

  Next, an N-methylpyrrolidone solution of a polyimide precursor (trade name: U varnish, Ube Industries, Ltd.) is applied to the surface of an aluminum cylindrical mold having an outer diameter of 31 mm and subjected to blasting on the surface in the same manner as the belt body. Co., Ltd.) was applied by a flow coating method and spin-dried. Further, the coating film was baked at 380 ° C., and then the formed coating film was removed from the core surface, and then cut into a ring shape having a width of 8 mm to obtain a concave groove forming member having an inner diameter of 31 mm and a wall thickness of 50 μm.

And after covering a masking material over 4 mm from the edge of the both ends of a belt main body, the coating layer containing PFA is not provided. After applying silicone rubber (LSR), the concave groove forming member having an inner diameter of 31 mm was inserted into both ends of the belt main body, and the bonding agent was cured at 200 ° C. Thereafter, by removing the masking material, a lubricant holding portion having a concave groove was formed.
Thereby, the endless belt provided with the lubricant holding part 20c having the concave groove 29 as shown in FIG. 3 was obtained. The depth (D in FIG. 3) of the formed groove was 4 mm, and the width (H in FIG. 3) was 0.43 mm.

(Comparative Example 1)
First, an N-methylpyrrolidone solution of a polyimide precursor (trade name: U Varnish, Ube Industries, Ltd.) was applied to the surface of an aluminum cylindrical mold having an outer diameter of 30 mm subjected to blasting by a flow coating method. After spin-drying, a fluororesin (PFA) dispersion solution (trade name: 710CL, manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) was coated by spray coating, and then the coating film was baked at 380 ° C. An endless belt having a total length of 352 mm, in which a coated film having a film thickness of 25 μm containing PFA as a thermoplastic resin is formed on the outer periphery of a polyimide resin having a film thickness of 70 μm, is removed from the core surface, and both ends are cut off Obtained.
This was used as the endless belt of Comparative Example 1.

<Evaluation>
The evaluation when the endless belt manufactured in Examples 1 to 3 and the endless belt of Comparative Example 1 are attached to the fixing device and this fixing device is further attached to the image forming apparatus will be described.
For the evaluation, the fixing device 30 shown in FIG. 4 provided with the meandering prevention member 90 shown in FIG. 5 was used. After the endless belts of Examples 1 to 3 and Comparative Example 1 were attached to the fixing device, respectively. The fixing device was attached to the image forming apparatus shown in FIG.
Image printing is performed by this image forming apparatus, and the fixing device is image-formed every 50,000 sheets, 100,000 sheets, 150,000 sheets, 200,000 sheets, 250,000 sheets, and 300,000 sheets. It was taken out from the apparatus and the endless belt end (end face) was checked for damage.

  The heat fixing roll 31 in the fixing device 30 is a pipe made of a carbon steel pipe having a thickness of 0.5 mm and an outer diameter of 25 mm, and a silicone rubber (LSR manufactured by Shin-Etsu Chemical Co., Ltd.) is 0.6 mm in thickness and the outermost surface layer. A 30 μm thick PFA tube (950 HP-Plus manufactured by Mitsui DuPont Fluorochemical Co., Ltd., extruded and subjected to excimer laser treatment) is integrally cast so as to be integrally coated.

  In the evaluation, 2.0 g of amine-modified silicone oil as a lubricant was added to the lubricant holding member 40 and the endless belt 32 was attached to the fixing device. Further, as an acceleration condition for confirming the durability of the end of the endless belt, the pressure (nip pressure) in the contact area between the heat fixing roll 31 and the endless belt 32 was set to 1.3 times the usual.

As a result of the evaluation, all of the endless belts of Examples 1 to 3 were able to print up to 300,000 sheets without any problem. Further, almost no oil leakage was observed from the end of the endless belt. In particular, in Example 3, no oil leakage was observed.
Further, in the endless belt of Example 1, partial peeling of the porous body was observed at the end of 300,000 sheets, but in the endless belt of Example 2 to which the reinforcing member was applied, the porous body was not peeled off at all. I couldn't see it.
On the other hand, in the endless belt of Comparative Example 1, oil leakage starts from the end of the belt from the end of 50,000 sheets, and is small at the end (end surface) of the belt at the end of 150,000 sheets. Cracks began to appear, and at the end of 290,000 sheets, the end of the belt broke, making it impossible to print.

It is sectional drawing which shows one Embodiment of the endless belt of this invention. It is sectional drawing which shows one Embodiment of the endless belt of this invention. It is sectional drawing which shows one Embodiment of the endless belt of this invention. 1 is a schematic configuration diagram illustrating an embodiment of a fixing device of the present invention. It is the schematic which showed the structure of the meandering prevention member provided in the fixing apparatus of this invention. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus of the present invention. It is sectional drawing which shows the layer structure of the conventional endless belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Belt main body 12 Base layer 14 Cover layer 20 Lubricant holding | maintenance part 22 Porous body 24 Reinforcement member 26 Groove formation member 28 Bonding agent 29 Groove 30 Fixing device (transfer means)
31 Heat-fixing roll 32 Endless belt 36 Press member 41 Photosensitive drum (image carrier)
42 Charger (charging means)
43 Laser exposure device (latent image forming means)
44 Developer (Developer)
50 Secondary transfer part (transfer means)
90 Meander prevention member

Claims (9)

  An endless belt comprising a lubricant holding portion for holding a lubricant at one or both ends of a belt main body.   The endless belt according to claim 1, wherein the lubricant holding portion is provided on an inner peripheral surface of the belt main body.   The endless belt according to claim 1, wherein the lubricant holding portion is provided on an outer peripheral surface of the belt main body.   The endless belt according to claim 1, wherein the lubricant holding portion includes a porous body.   The endless belt according to claim 4, further comprising a reinforcing member for reinforcing the porous body.   2. The endless belt according to claim 1, wherein the lubricant holding portion has a concave groove that opens outward in parallel with the belt axial direction along a circumferential direction of an end face of the belt main body.   A fixing member, an endless belt having a lubricant holding portion for holding a lubricant at one or both ends of the belt main body, and an inner end of the endless belt, wherein the endless belt is pressed against the fixing member to And a pressing member that forms a contact portion between the fixing member and the endless belt.   The fixing device according to claim 7, further comprising a meandering prevention member that is in contact with an end surface of the endless belt and prevents meandering of the endless belt. An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming a latent image on the surface of the image carrier, and a developing unit for developing the latent image with toner to form a toner image And a transfer means for transferring the toner image to a recording medium, and a fixing means for heating and fixing the toner image to the recording medium,
The fixing means is disposed on a fixing member, an endless belt that includes a lubricant holding portion that holds a lubricant at one or both ends of the belt body, and the endless belt is disposed inside the endless belt. An image forming apparatus comprising: a fixing device having a pressing member that presses against the pressing member to form a contact portion between the fixing member and the endless belt.

Images